Relationship Between Device-detected Subclinical Atrial Fibrillation and Heart Failure in Patients with Cardiac Resynchronization Therapy Defibrillator

Background: Atrial fibrillation (AF) is a leading preventable cause of heart failure (HF) for which early detection and treatment is critical. Subclinical-AF is likely to go untreated in the routine care of patients with cardiac resynchronization therapy defibrillator (CRT-D).

Hypothesis: The hypothesis of our study is that subclinical-AF is associated with HF hospitalization and increasing an inappropriate therapy.

Methods: We investigated 153 patients with an ejection fraction less than 35%. We divided into three groups, subclinical-AF (n = 30), clinical-AF (n = 45) and no-AF (n = 78). We compared the baseline characteristics, HF hospitalization, and device therapy among three groups. The follow-up period was 50 months after classification of the groups.

Results: The average age was 66 ± 15 years and the average ejection fraction was 26 ± 8%. Inappropriate therapy and biventricular pacing were significantly different between subclinical-AF and other groups (inappropriate therapy: subclinical-AF 13% vs clinical-AF 8.9% vs no-AF 7.7%: P = .04, biventricular pacing: subclinical-AF 81% vs clinical-AF 85% vs no-AF 94%, P = .001). Using Kaplan-Meier method, subclinical-AF group had a significantly higher HF hospitalization rate as compared with other groups. (subclinical-AF 70% vs clinical-AF 49% vs no-AF 38%, log-rank: P = .03). In multivariable analysis, subclinical-AF was a predictor of HF hospitalization.

Conclusions: Subclinical-AF after CRT-D implantation was associated with a significantly increased risk of HF hospitalization. The loss of the biventricular pacing and increasing an inappropriate therapy might affect the risk of HF hospitalization.